1. Field of the Invention
The present invention relates to a method and a device for the continuous casting of molten metal, particularly steel, on a roll.
2. Description of the Related Art
These prior art devices essentially comprise a roll with a horizontal axis rotating about its axis and equipped with powerful means for cooling its outer wall. This roll receives the molten metal from a container which comprises an inclined front wall, the free upper edge of which, via which the molten metal tends to be poured, is swept by the surface of the casting roll. This roll/container interaction takes place in a contiguous manner in order to avoid any leakage of molten metal between them.
The roll is thus supplied upstream of its upper generatrix relative to the direction of flow of the product. Due to the roughness and rotation of the roll, the molten metal is deposited on the latter and, through the effect of rotation, is entrained out of the bath in order to leave the roll when its cooling is sufficient. It is thus possible to obtain steel products whose thickness is less than 1 mm.
In fact, the solidified thickness of metal, when it leaves the roll, quite obviously depends on the duration of contact with the roll and on the efficiency of the cooling performed.
Because the molten metal is supplied upstream of the upper generatrix of the roll, the molten metal, which adheres to the cold wall of the roll, has firstly to rise up to this upper generatrix before coming back down slightly and leaving the surface of the roll. In some cases, it comes about that the roughness of the roll alone becomes insufficient to entrain the product at the start of the casting. In fact, at that moment, the lead angle, that is to say the angel at the center of the roll intersecting the arc located between the point at which the cast metal comes into contact with the roll and the horizontal, may be relatively small. The value of this angle, it will be understood, varies as the length of the arc of contact of the cast metal with the roll, which arc, for a given speed of rotation of the roll, determines a duration of contact and thus the thickness of the product.